by Dr. Günther Neumeier

Polychlorinated biphenyls (PCB’s) are chlorinated aromatic hydrocarbons, first synthetizised in the middle of the 19th century (1864)on a laboratory scale. Commercially they are manufactured by progressive chlorination of biphenyl in the presence of a suitable catalyst (e.g. iron III - chloride). Depending on the reaction conditions the chlorination can lead to the replacement of 1-10 hydrogen atoms by chlorine.

Formula: C₁₂ H_10-n Cl_n ( with n = the number of chlorine atoms)

With respect to the different number of chlorine atoms and the different positions they can have in the molecule, theoretically 209 compounds (isomers and congeners) are possible, but only about 130 of these are likely to occur in commercial products or mixtures (Safe,1990).

Because of their physico-chemical properties PCB’s have been used since 1929 as insulating fluids in transformers and capacitors, as hydraulic oils, lubricants, softeners,heat exchange fluids, additives in plastics, casting oils etc.,and are still in use today.Most of the PCB’s were produced during the period 1950 to 1983. Total world production has been estimated to be more than 1 million metric tonnes.

PCB’s were first detected in environmental samples in 1966 (S.Jensen,1966). Subsequent research has shown PCB’s to be ubiquitously present, both in human beings and the environment. This is due to their persistence in the environment, their ability to be distributed over large distances ( even to areas where they have never been produced or used),their potential for bioaccumulation in organisms and biomagnification in the foodchain.Their harmful effects to man and the environment are well documented in a number of reviews (WHO,1976; IARC,1978; OECD,1982; Lorenz & Neumeier,1983; Kimbrough,1987; IARC,1987; DFG,1988; ATSDR,1989;WHO,1989; WHO,1993; ATSDR,1996;).

The PCB’s produced in Germany were manufactured by the only German producer , the Bayer corporation. The trade name of the produced PCB-mixtures was Clophen A. According to their main congeners the technical mixtures have been labelled as:

Clophen A30 ( 56% trichlorobiphenyls, mean chlorine content: 42%)

Clophen A40 ( 50% tetrachlorobiphenyls, mean Cl content:48,6%)

Clophen A50 ( 44% pentachlorobiphenyls, mean Cl-content: 54,3%)

Clophen A60 ( 43% hexachlorobiphenyls, mean Cl-content: 59%)

Data on the total production volume (best estimate available) , the quantities imported (mainly for the production of capacitors) and exported ( use of PCB’s in transformers and capacitors) and the resulting domestic supply is given in the table below.

Since their introduction PCB’s have been used in both"open systems" and "closed systems" as well.

Open systems are systems where PCB’s are "consumed" during their use, or unrecoverable after their use/lifetime of the products. Open systems release the PCB’s successively to the environment. The lifespan of the open-system products ranges from some years to more than 50 years (e.g. sealants in buildings).

As the use of PCB’s in "open systems" ceased in Germany after the selfimposed restriction of the Bayer Corp. in 1972, an ongoing emission of PCB’s into the environment until the year 2010 - or even longer - has to be taken into account.

With the 10 ^th Ordinance under the Federal Immission Control Act of July 26,1978, implementing the Council Directive of the European Economic Community (76/769/EEC) into German Law , the marketing of PCB’s for use in "open systems" has been banned.

The applications for "open systems" are shown in table 2.

"Closed Systems" are defined in the above mentioned Council Directive of the European Economic Community (76/769/EEC). Of the uses specified there, only the use in transformers and capacitors and as hydraulic oil in underground mining plays a role in Germany. However, the use of PCB’s in small capacitors and as hydraulic fluids in underground mining machines is certainly not a ? closed use? , because most of the used PCB is consumed, or can not be recovered and is therefore emitted to the environmental compartments. With respect to the use in capacitors,about 10000 tonnes of PCB’s have been used for the production of small capacitors ( containing less than 1kg PCB), mostly (about 90% ~ 9000 tonnes) in capacitors for the ignition of neon tubes.

Table 3 gives an overview of the amount of PCB used in "closed systems".

Remainder (1500 tonnes) : Earching Coils, Hydraulic Fluid

( Military)

According to the German PCB Prohibition Ordinance of 18 July 1989, preparations, products and substances containing more than 50 mg PCB / kg may no longer be produced , placed on the market and used.In addition, capacitors with more than 1 liter of PCB containing liquid had to be taken out of use by 31 December 1993, other products (transformers) have to be phased out by 31 December 1999.

As PCB’s have not been produced in Germany since 1984/1985, there are no emissions due to the production today. In order to calculate emissions from open- and closed systems by use of ‘emission factors’ it is necessary to estimate the amount of PCB still in use.

The quantification of PCB’s in open systems still in use is very difficult. Although the use of PCB’s in varnishes, inks,special papers, plastics, sealants etc. ceased in the early 1970s and therefore most of the use and emissions of PCB’s occurred in earlier years, there is still a certain amount in use, for instance in sealing materials in buildings. PCB emissions from open uses in Germany have been calculated by the ifeu-Institute / Heidelberg, based on analysis of PCB-containing sealants, the assumption of a 50% release until 1972 and the application of an estimated emissionfactor of 7% per year.

By definition, closed systems should not emit PCB’s at all. However, some uses - originally classified as ‘closed systems’ - are not really closed. This is especially true for the use of PCB - containing hydraulic fluids in underground mining.Despite the fact that no exact data are available on the extent of PCB entry into the environment via ventilation systems, mine output and pit water, it must be assumed that most of the PCB used in that sector has been released into the environment in the past, as the recovery rate has been very low.As PCB’s have been substituted in hydraulic fluids during the 1980s , there are no more emissions from that source today.

Small capacitors are still in use in old (manufactured before 1989) electrical appliances such as oil burners, washing machines, hair dryers, neon tubes and dishwashers. However - as just shown before - the main amount has been used as ignition capacitors in neon tubes ( about 10000 tonnes PCB). Out of these 10000 tonnes 3400 were still in use in 1994. The annual emission into air from that source was estimated to be about 6 tonnes in 1990. In the year 2000 the emission should be zero because of the lifetime of these systems. Up to then , and even some years longer, it will be essential to collect these small electrical appliances separately in order to avoid that they are land filled or burnt together with municipal waste.

Transformers and large capacitors are considered to be the classical ‘closed systems’. It is however known from practical experience that ~ 2% of the transformers lose about 30 kg/year (emission factor : 0.06 %/year), and that ~ 3% of the large capacitors lose 8 kg/year (emission factor: 1.6 %/year). With these emission factors and the numbers of transformers and capacitors in use in 1994 , taking into account that only 10% of the total emission is emitted into the air , a total emission of 11 tonnes PCB into the air has been estimated (ifeu, 1998). Together with other sources of minor relevance , the PCB emission inventory for 1994 is shown in table 4.

Source PCB (t/y)

________________________________________________________

Open applications 16

Closed systems 11

Firing installations 0.8

Secondary steel production 0.2

Others 0.15

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Total 28.15

An essential measure to reduce further emissions of PCB’s from used and phased out PCB-containing equipment is their complete collection, safe storage and proper disposal or destruction.

PCBs applied in open systems or used otherwise are normally released into the environment and not recoverable. PCBs used in sealants may however be collected when the buildings where they have been used are demolished.They can be burnt in high temperature incinerators. As the application of PCB’s in sealants makes up a major part of the ‘open’ PCB use this is an important way to reduce further emissions. PCB’s from other open use are to a large extent destroyed if they are not dumped in waste sites but burnt together with household waste in modern municipal waste incinerators.

Although the emissions from closed systems (capacitors, transformers) are relatively small during their use, they may be a significant source after their use when they are not properly stored, disposed of or destroyed.

Small capacitors, which are normally disposed of together with municipal waste, can be collected to a considerable extent if the small electrical appliances are collected separately.This is especially important for the ignition part of neon tubes.In Germany about 30-40% of these small electrical appliances are collected separately nowadays.

Big capacitors and transformers have to be collected, disposed of and the liquids burnt or recycled according the existing legislation.

Table 5 gives an overview of how these systems are handled in Germany.

In order to protect man and the environment against additional exposure to PCB’s and the subsequent harmful effects a ban of the production , marketing and use of PCB’s in the near future is necessary and possible( see the experience in OECD-countries). In addition to that measure the identification of areas of use (inventory), labelling of PCB containing equipment, control of the phasing out and safe disposal and/or destruction of PCB’s together with accompanying legal regulations are indispensible.

ATSDR (1989) Toxicological profile for selected PCBs (Aroclor 1260, 1254, 1248, 1242, 1232, 1221 and 1016), Atlanta, Georgia, Agency for Toxic Substances and Disease Registry (ATDSR/TP-88/21).

ATSDR (1995) Draft Toxicological profile for polychlorinated biphenyls (update), Atlanta, Georgia, Agency for Toxic Substances and Disease Registry.

DFG (1988) Polychlorinated biphenyls, German Association for the Encouragement of Research: Communication XIII of the Government Committee on the Testing of Residues in Foods, Weinheim, Verlag Chemie (in German).

IARC. 1978. Polychlorinated biphenyls and polybrominated biphenyls, Lyon, International Agency for Research on Cancer, pp. 43-103 ( IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans. Volume 18 ).

IARC. (1987) Overall evaluation of carcinogenicity: An updating of IARC monographs Volumes 1 to 42, Lyon, International Agency for Research on Cancer, (IARC Monographs on the Evaluation of the Carcinogenic Risks of Chemicals to Humans, Supplement 7).

ifeu (1998) Draft Report ‘Ermittlung von Emissionen und Minderungsmaßnahmen für persistente organische Schadstoffe in der Bundesrepublik Deutschland’(research project on behalf of the Federal Environmental Agency), ifeu-Institut für Energie-und Umweltforschung Heidelberg GmbH, Heidelberg, May 1998.

JENSEN, (1966) Report of a new chemical hazard, New Scientist, 32, 612.

KIMBROUGH, R.D. (1987) Human health effects of polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs). Annu. Rev. Pharmacol. Toxicol., 27: 87-111.

LORENZ, H. and NEUMEIER, G. (1983) Polychlorinated biphenyls (PCBs). A joint report of the Federal Health Office and the Federal Environmental Agency. Munich, MMV Medizin Press (BGA Publication No. 4/83) (in German).

OECD (1982) Report on the implementation by member countries of the decision by the Council on the Protection of the Environment by control of polychlorinated biphenyls, Paris, Organisation of Economic Co-operation and Development (ENV/CHEM/81.2).

Safe, S. Crit.Rev.Toxicol. 21:51-88 (1990)

WHO (1976) Environmental Health Criteria 2: Polychlorinated biphenyls and terphenyls, Geneva, World Health Organization, 85 pp.

WHO (1993) Environmental Health Criteria 140: Polychlorinated biphenyls and terphenyls (second edition), Geneva, World Health Organization, 682 pp.